What are the different kinds of iPods?

I want to buy an iPod for the holidays, but I don't understand what the differences are or which would be the best one to buy. Which model iPod is the best?

It really depends on what you are looking for. I have outlined the capacity and differences between the various models below:

iPod - This is the largest of the iPod family, and the "original". Its dimensions are 2.4 x 4.1 x .43 inches. It has a full color 2.5 inch screen, and weighs between 4.8 ounces and 5.5 ounces depending on the storage size (30 or 60 gigabytes). Unlike the iPod Nano or iPod Shuffle, it can play videos, including TV shows and music vidoes downloaded fromt he iTunes music store. The 60 Gb iPod can hold up to 15,000 songs, 25,000 photos or over 150 hours of video. It comes in black, white or a special U2 edition.

iPod Nano - This unit is maller than the iPod, and cheaper too. Its dimensions are 1.6 x 3.5 x .27 inches, Apple compares its thickness to that of a pencil. It also has a full color screen to help you manage your music, but it can not play videos. Storage options for the iPod Nano are 1, 2 or 4 Gigabytes in size.The 4 Gigabyte iPod Nano can hold up to 1,000 songs or 25,000 photos. It comes in black or white (no U2 edition)

iPod Shuffle - This is the smallest and cheapest iPod. Its dimensions are 3.3 x .98 x .33, or about the size of a pack of gum. It does not have a screen at all and instead uses a slider control on the back to choose how your songs will be played, either in order of "shuffled" where the iPod randomly chooses songs for you. (The shuffle feature is also available on the iPod and the iPod Nano). It comes in 512 Megabytes or 1 Gigabyte in size. The 1 Gigabyte size can hold approximately 240 songs.